The MTN Qhubeka rider secured his 12th victory of the season by holding off Boom and Van Hoecke after 204.8km from Middlesbrough to Goes.
The first major attack came early, with 15 riders breaking away from the peloton, before being reeled back in with 20km remaining.
Kevin Hulsman’s was the next to attack but was again caught by the peloton, before Luca Ascani formed a solo break 10km from the finish.
Van Rensburg, Boom and Van Hoecke combined to catch Ascani before dropping the Italian shortly afterwards.
The 23-year-old from Pretoria then had just enough left to outsprint Boom and Van Hoecke.